The on-loan striker made a promising start to his career with a debut goal at Wolves before questioning his treatment at Eastlands.
"The club’s view on me changed when Roberto Mancini came in. But I have a huge respect for the man," said Manu.
"However, it’s more than strange. When you have a player like myself who they suddenly say is not good enough, I went to Real Madrid, played, and scored goals.
"I came back here to prove to everyone else that I’m still a good footballer.
"For me, if you don’t allow me to train with a professional team, there is something wrong there.
"So, for me, it’s over. I have to take the positives out of it. I have the chance to play for Tottenham and that’s all that matters now.”